The program tries to equations using "nNumber" "nDigit's" to obtain answers 1 to "MaxN" with specified operation



four4 [nDigit nNumber MaxN [+] [-] [*] [/] [^] [sqrt] [percent] [fact] [neg] [repeat]]



sqrt: sqaure root

percent: %, i.e. divide by 100

fact: factorial

neg: negation, allow -4

^: exponentiation

repeat: allow repeating fraction, i.e. .(4)' = 0.44444 = 4/9



0 <= nDigit <= 9



Example:

  PUZZLE

  PUZZLE 4 4 100 (using four 4's to make 1 to 100)

  PUZZLE 2 2 10  (using two 2's to make 1 to 10)

  PUZZLE 3 4 100 (using four 3's to make 1 to 100)

  PUZZLE 4 4 100 + - * / (using four 4's to make 1 to 100, allow only + - * / as operation)



v0.40



Compute four 4's, 1 to 100, with only + - * /, only output if a number can be formed



v0.65



Add check to prevent overflow error

Add unary operation, sqrt, factorial, percent, negation

Add binary operation, power

Add the option to adjust to any digit, any number, and any binary/unary operation



v0.67



Add checks to avoid overflow

Add some optimizations so the code runs slightly fasters



v0.80



Add expression tree to record expression, output result in pre-order



v0.90



Change the expression tree to an acylic graph with hash table on every node.



v0.92



Add priority to every node, also add output in infix notation

Change it so that repeating fraction of 0.4 is displayed as 0.(4)' not 0.444444



v0.94

	

Add codes to fix round-off error.  I.e. 28.4/0.4 != 71 in double, thus, I add some check against this situation



v0.96



Add codes to guard against 0.4 ^ (4 ^ 44) != 0



v1.00



Add the command-line input

Remove output in pre-order notation